Re: [eigen] cache queries bug?

[Benoit Jacob <jacob.benoit.1@xxxxxxxxx>]

Thanks!

You are allowed to sleep now (but not too long).

Benoit

2010/6/26 Gael Guennebaud <gael.guennebaud@xxxxxxxxx>:
> should be fine now.
>
> gael
>
> On Sun, Jun 27, 2010 at 12:03 AM, Ben Goodrich <bgokgm@xxxxxxxxxxxxxx> wrote:
>> Hi,
>>
>> On Sat, Jun 26, 2010 at 5:19 PM, Gael Guennebaud
>> <gael.guennebaud@xxxxxxxxx> wrote:
>>> hi,
>>>
>>> I've just added a small utility to help debugging this. So could you
>>> please update your local copy, and send me back the output of the
>>> following commands:
>>>
>>> $ cd path_to_eigen/bench
>>> $ g++ check_cache_queries.cpp -I .. && ./a.out
>>
>> I get no output in over 3 minutes of CPU time. On the core duo it
>> spits out all the info almost instantly, but I imagine you already
>> know what that says.
>>
>>> Also could you retry ./check cholesky ? I've also committed a small
>>> fix which could partially solve the issue.
>>
>> Still hanging on cholesky_2.
>>
>> Ben
>>
>>> On Sat, Jun 26, 2010 at 8:40 PM, Ben Goodrich <bgokgm@xxxxxxxxxxxxxx> wrote:
>>>> Hi,
>>>>
>>>> If you want to postpone this until after the beta is released, that is fine.
>>>>
>>>> I have two machines, both with the "same" software (disregarding the
>>>> bitness difference) with Debian unstable and g++ 4.4.4.
>>>>
>>>> One is a core duo desktop from a couple of years ago
>>>>
>>>> bgoodrich@Room320:/tmp/eigen/test$ cat /proc/cpuinfo
>>>> processor       : 0
>>>> vendor_id       : GenuineIntel
>>>> cpu family      : 6
>>>> model           : 15
>>>> model name      : Intel(R) Core(TM)2 CPU          6300  @ 1.86GHz
>>>> stepping        : 6
>>>> cpu MHz         : 600.000
>>>> cache size      : 2048 KB
>>>> physical id     : 0
>>>> siblings        : 2
>>>> core id         : 0
>>>> cpu cores       : 2
>>>> apicid          : 0
>>>> initial apicid  : 0
>>>> fpu             : yes
>>>> fpu_exception   : yes
>>>> cpuid level     : 10
>>>> wp              : yes
>>>> flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
>>>> mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe
>>>> syscall nx lm constant_tsc arch_perfmon pebs bts rep_good aperfmperf
>>>> pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm lahf_lm
>>>> tpr_shadow
>>>> bogomips        : 3721.67
>>>> clflush size    : 64
>>>> cache_alignment : 64
>>>> address sizes   : 36 bits physical, 48 bits virtual
>>>> power management:
>>>>
>>>> processor       : 1
>>>> vendor_id       : GenuineIntel
>>>> cpu family      : 6
>>>> model           : 15
>>>> model name      : Intel(R) Core(TM)2 CPU          6300  @ 1.86GHz
>>>> stepping        : 6
>>>> cpu MHz         : 600.000
>>>> cache size      : 2048 KB
>>>> physical id     : 0
>>>> siblings        : 2
>>>> core id         : 1
>>>> cpu cores       : 2
>>>> apicid          : 1
>>>> initial apicid  : 1
>>>> fpu             : yes
>>>> fpu_exception   : yes
>>>> cpuid level     : 10
>>>> wp              : yes
>>>> flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
>>>> mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe
>>>> syscall nx lm constant_tsc arch_perfmon pebs bts rep_good aperfmperf
>>>> pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm lahf_lm
>>>> tpr_shadow
>>>> bogomips        : 3720.69
>>>> clflush size    : 64
>>>> cache_alignment : 64
>>>> address sizes   : 36 bits physical, 48 bits virtual
>>>> power management:
>>>>
>>>> and one is a really old laptop (don't laugh)
>>>>
>>>> goodrich@X41Laptop:/tmp/eigen$ cat /proc/cpuinfo
>>>> processor       : 0
>>>> vendor_id       : GenuineIntel
>>>> cpu family      : 6
>>>> model           : 13
>>>> model name      : Intel(R) Pentium(R) M processor 1.50GHz
>>>> stepping        : 8
>>>> cpu MHz         : 600.000
>>>> cache size      : 2048 KB
>>>> fdiv_bug        : no
>>>> hlt_bug         : no
>>>> f00f_bug        : no
>>>> coma_bug        : no
>>>> fpu             : yes
>>>> fpu_exception   : yes
>>>> cpuid level     : 2
>>>> wp              : yes
>>>> flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
>>>> mca cmov clflush dts acpi mmx fxsr sse sse2 ss tm pbe nx up bts est
>>>> tm2
>>>> bogomips        : 1196.71
>>>> clflush size    : 64
>>>> cache_alignment : 64
>>>> address sizes   : 32 bits physical, 32 bits virtual
>>>> power management:
>>>>
>>>> On the 32 bit laptop, I have encountered a problem where things like
>>>>
>>>> ./check.sh cholesky
>>>>
>>>> hang for minutes before I kill them, while on the 64 bit core duo
>>>> desktop, this finishes in a few seconds.
>>>>
>>>> I bisected the problem to
>>>>
>>>> goodrich@X41Laptop:/tmp/eigen$ hg bisect --bad
>>>> The first bad revision is:
>>>> changeset:   3027:c93abfa8ffcb
>>>> parent:      3023:c3b8e6edde53
>>>> user:        Gael Guennebaud <g.gael@xxxxxxx>
>>>> date:        Wed Jun 23 16:34:51 2010 +0200
>>>> summary:     fix cache queries for non core2 CPU ;)
>>>>
>>>> But I don't know what to do from here because I don't really
>>>> understand low-level issues like this.
>>>>
>>>> Thank you,
>>>> Ben
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>
>>
>>
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